Inspection of Gas-fired Forced-air Furnaces will prolong your life expectancy. Two Most Common Types of furnaces are the High-efficiency and Standard-efficiency Natural Gas Furnace. They are usually either up-draft or down-draft models. Up-draft is by far the most common.
Over the last 20 years, a new generation of higher efficiency gas furnaces and boilers has come to market. An essential difference in the design of these units is how they are vented, eliminating the need for dilution air. The combustion of gas produces certain by-products, including water vapour and carbon dioxide.
In a conventional gas furnace, such by-products are vented through a chimney, but a considerable amount of heat (both in the combustion products and in heated room air) escapes through the chimney at the same time. Heat is also lost up the chimney when the furnace is off.
The newer designs have been modified to reduce the amount of heated air that escapes during the on and off cycles and by extracting more of the heat contained in the combustion by-products before they are vented.
Common components of gas furnaces and their systems. A typical gas furnace is constructed with a cabinet, distribution system, heat exchanger, fan and controls and a thermostat. There are many other systems that can be added to your furnace such as humidifers, electronic filters and HRV units which can improve your air quality in your home.
Inspection and Testing of Conventional Gas Furnace. There are usually a minimum of four inspection steps performed on a typical gas furnace which are;
1. Remove burner and fan cover with power turned off.
2. Check the heat exchanger.
3. Start the furnace and inspecting flame, exhaust system.
4. Check the duct system and air flow through ducts and return air systems.
Life Expectancies of Furnaces
Conventional gas furnaces will typically last 20 – 25 years and are usually replaced when heat exchanger fails. Although some furnaces have been known to last over 35 years without failing. Having your furnace regularly serviced by a trained technician can greatly enhance its life expectency.